In the conventional intra-mold molten resin flow analysis (simulation) for injection-molding a plastic resin material, an extensively employed approach has been used to divide a form model of the molded product into numerous micro-elements as shown in FIG. 1, and to compute their behavior by solving motional equations, continuity equations, and energy equations of the fluid by the use of a finite element method, boundary element method, difference method, and other numerical analytic techniques.
Under any such intra-mold molten resin flow analytical method, it is by inputting and computing the parameters of a resin selected and the molding operating conditions including a resin temperature, mold temperature, and filling speed, that a fill pattern (see FIG. 2) indicating the resin filling progress status (times) may be acquired through individually predesignated calculations.
None of the conventional resin flow analytical methods just discussed, however, incorporate any means to tell if the conditional input settings have been appropriate, look for even more appropriate input settings, or judge which of a number of sets of conceivable conditional input settings is best suited for purposes at hand. In consequence, empirical knowhow has had to be relied on that is acquired only through undertaking repeated comparative studies on analytical findings against actual moldings, in order to assess the validity of computed results.
Thus, the conventional intra-mold resin flow analytical method has been employed primarily for assessing the validity of physical configurations of a molded product (such as its wall thicknesses, gate locations and count, runner dimensions, etc.) by inputting the resin temperature, mold temperature, filling speed, and other parameters that have been gained in advance by empirical knowledge, and no attempts have yet been made to evaluate the appropriateness of molding conditions.
Nevertheless, the intra-mold resin flow analysis should originally address by programmed operations the task of judging molding feasibilities and degree of difficulty and deriving the requirements for producing a given molded product, at a stage when the product design is complete but before making its mold, and is demanded not only to assess the mold form-related appropriateness (of wall thicknesses, gate locations and count, gate and runner dimensions, etc.), but also to compute to derive appropriate molding condition ranges and optimum molding conditions. Ultimately, the determination of all the molding operating conditions is looked forward to of the resin flow analysis.
Accordingly, the objective of this invention is to provide a molten injection-molding material flow analysis evaluating method under which by utilizing the equitime curve diagrams of a conventional mold fill pattern for the molten material flow analysis over a given mold, and by deriving each individual filling speed from the distance between individual equitime curves, the speed variation behavior during a filling cycle may be displayed to enable evaluating, and assessing the appropriateness of, input filling speed settings.